Impact of the development of agricultural land on the transmission of sleeping sickness in Daloa, Cote d'Ivoire

Although tools to control sleeping sickness do exist, their use is difficul t; areas where intervention is most required often cannot be targeted for l ack of appropriate risk indicators. The importance of human behaviour and h abits in the manifestation of the disease is clear. In the development of e ffective new approaches to the control of the disease, information must be gathered about human populations, and their interaction with the environmen t, in rural as well as in urban and peri-urban areas. The results of a stud y carried out in Daloa show that use of some methods for the development of agricultural land leads to increased human-vector contact and, as a result , increased risk of sleeping sickness. Such land-management methods may the refore be useful as risk indicators for transmission. Transmission does not occur in the town of Daloa itself but in surrounding areas under cultivati on. The use of the epidemiological risk index seems to be inappropriate in urban (and perhaps peri-urban) areas. The results emphasise not only the im portance of environmental and demographic data in elucidating the epidemiol ogy of human trypanosomiasis but also the need for further investigations i n peri-urban areas.